Non-snap-acting switch devices with s-shaped contact spring blade

ABSTRACT

A switching device including a casing, a pair of fixed contacts in the casing, a flexible member in the casing carrying and biasing a movable contact against one of the fixed contacts, an actuator engaging the flexible member and movable relative to the casing to displace the member and transfer the movable contact out of engagement with the fixed contact and a second movable contact mounted on the member into engagement with the other fixed contact, and terminals accessible from the exterior of the casing which are electrically connected to the movable contact and to the fixed contacts.

United States Patent Bowen et al.

4 1 Aug. 8, 1972 [54] NON-SNAP-ACTING SWITCH DEVICES 2,817,725 12/1957 Rochfort et al. ...200/ 153 T X WITH S-SHAPED CONTACT SPRING 3,260,828 7/ 1966 Cartier ..200/ 166 J X L DE 3,291,931 12/1966 Rogers ..200/166 J X 3,194,933 7/1965 Ramstetter ..200/166 1 [72] Inventors: John W. Bowen, Columbus; Donald 2,749,396 6/1956 Horman etgalinvzoolmfi J X D. Perkins, Worthington, both of Ohlo Primary Examiner-Robert K. Schaefer [73] Assignee: Columbus Electric Manufacturing Assistant y Co Columbus, Ohio Att0rneyStrauch, Nolan, Neale, Nies 81. Kurz [22] Filed: March 4, 1971 57 ABSTRACT PP N03 120,989 A switching device including a casing, a pair of fixed contacts in the casing, a flexible member in the casing [52] CL "200/166 J 200/164 R 200/172 A carrying and biasing a movable contact against one of 51 int. Cl. 3110111 1/1s H01h 3/04 the fixed engaging the flexible [58] Field of Search 200/166 J 166 159 A member and movable relative to the casing to displace T ZOO/1'53 v 172 the member and transfer the movable contact out of engagement with the fixed contact and a second movable contact mounted on the member into engagement with the other fixed contact, and terminals [56] References. Clted accessible from the exterior of the casing which are UNITED STATES PATENTS electrically connected to the movable contact and to the fixed contacts. 3,163,738 12/1964 Farrell ..200/166 1 3,433,917 3/ 1969 l-lufnagel ..200/ 166 J 9 Claims, 4 Drawing Figures 5484 86 f 64 70 22 F 72 5a 2e 90 2B 02 z 24 68 so so 76x L "r PATENTEDMJG 8 m2 3,683,14

H 2 mvm'roas JOHN W. BOWEN DONALD D. PERKINS ATT RNEYS This invention relates toswitchingdevices and, more particularly, to electrical switching devices of the nonsnap-acting type. g g

It is one importantand primary object of our invention to provide novel, improved, non-snap-acting switching devices.

In general, the novel switching-devices of the'present invention include a casing which surrounds a pair of fixed contacts located on opposite sidesof co operating movable contacts. An actuator slidably mounted'in the casing can be depressed to transfer the movable contacts out of engagement with oneof the fixed contacts and into'e'ngagement with the other fixedcontact.

To the extent just described, our novel switching devices resemble and have the advantages of the improved snap-acting switchesdisclosedin US. .Pat. Nos. 3,234,343 issued Feb. 8, 1966, for SUB-MINIATURE SNAP-ACTING SWITCH and 3,248,496 issued Apr. 26, 1966 for SNAP ACTING SWITCH HAVING A THIN LEAF SPRING WITH A PORTION'THEREOF BENT AT AN OBTUSE ANGLE TO THE REMAINDER. However, they'also have advantages not possessed by these snap-acting switches. Specifically, in many applications of electrical switching devices, snap action is not required. The cost of switching devices for such applications can be significantly reduced by employing switches in accord with the present invention in the stead of snap-acting switches such as those described in the patents identified above.

More specifically, the switches of the present invention are simpler than those disclosed in the foregoing patents. This results in a double savings-one in the cost of the switching device components and the other in the cost of assembling and adjusting the switching devices.

Still another advantage of the, novel switching devices described herein is that the operating forces can be extremely small-even lower than those required to operate sub-miniature snap-acting switches of the type disclosed in the above-mentioned US. Pat. No. 3,234,343. This is because the differentialbetween the operating and return forces of the operating mechanism disclosed herein is basically lower than that of a snap-type mechanism.

In conjunction with thesforegoing it is another important and primary object of thepresent invention to provide novel, improved, non-snap-acting, switching devices which can be made in small sizes and have other advantages of the switches disclosed in the patents cited above, but haveadvantages not possessed by the latter in applications where snap action is not needed.

The novel switching devices of thepresent invention also have advantages over conventional switches of the non-snap-acting type. One is that all of the moving parts are enclosed and thereby protected against foreign material from the surrounding environment. Conventional non-snap switches are mostlyopen blade stacks and are subject to malfunction because of the penetration of dirt and other. foreign material into the switch mechanism.

In'addition the novel switching devices of the present invention are much, smaller than conventional nonsnap switches. This is another important advantage for obviousreasons.

It will be apparent from the foregoing that another important and primary object of our invention resides in the provision of novel, improved switching devices which have advantages not possessed by conventional non-snap-acting switches such as those discussed above.

Our invention has a number of novel features and advantages in addition to those discussed above. Among these is a novel, S-shaped, flexible contact arm on which the movable contacts are mounted and which biases one of these contacts into engagement with the associated fixed contact. This novel contact arm permits the actuator tomove through a selected distance before the first-mentioned of the movable contacts moves away from the associated fixed contact and breaks the circuit completed througlf these contacts. Thus, this novel construction allows wider mechanical tolerances to be used in the equipment in which the switching devices of the present invention are employed since the equipment need not be designed to precludeall'm'ovement of the actuator in order to avoid unwanted circuit interruptions.

Preferably, one of the two fixed contacts is also mounted on aflexible contactarm in the practice of the present invention. In the transfer of contacts in a switch in which the fixed contacts are mounted on rigid or non-flexible arms, the actuator member or arm begins to deflect as soon as the movable contact carried by it reaches the fixed contact. As this occurs, the force required to move the actuator through the remainder of its stroke rapidly increases. This is undesirable in many applications of the present invention. Rapid increases in operating pressure as just described are eliminated by mounting the fixed contact in cantilever fashion on a flexible contact arm in accord with the present invention. As the movable contact reaches the fixed contact in a switch so constructed, the contact arm gives or deflects although the contacts remain in engagement because of the resiliency of the contact arms. The resultis that the rate of build-up of forces in the moving member andconsequently the rapid increase in required operating force are substantially reduced.

Another advantage ofusing the novel flexible contact arm just described is that it allows greater actuator tion, there is relative movement between the movable and fixed contacts as they meet; i.e., there is a wiping action of one contact across the other. Accordingly, in this novel construction, the contacts are self-cleaning.

Another feature of the present invention is its versatility. For example, even in their smallest sizes, our novel switching devices can be equipped with pivottype operators for operating the casing-mounted actuator. This is important as such operators can be used to advantage in many applications of miniaturized switching devices.

Certain primary objects of the present invention have been identified above. Other important, but more specific objects of the invention reside in the provision of novel, improved, non-snap-acting switching devices:

1. which are simpler and less expensive than otherwise similar snap-acting switches.

2. which have completely enclosed operating components and are therefore free from malfunctions attributable to the penetration of foreign matter to the operating mechanism.

3. which can be made smaller than conventional nonsnap-acting switches.

4. which are versatile.

5. which are desirably insensitive in that the actuator can be moved through a pre-selected portion of its stroke before contact disengagement occurs and which therefore permit relatively wide mechanical tolerances to be employed in equipment in which they are incorporated.

6. which reduce the increase in operating force which typically occurs in heretofore available switches when a movable contact reaches a fixed contact.

7. which have minimal contact bounce.

8. which have self-cleaning contacts.

9. which can be made to have extremely small operating forces.

l0. which have various combinations of the attributes listed above.

Other objects and features and further advantages of the invention will become apparent from the appended claims and as the ensuing detailed description and discussion proceeds in conjunction with the accompanying drawing, in which:

FIG. 1 is a side view of a switching device constructed in accord with the principles of the present invention, part of a side wall forming cover being broken away to show the internal components of the device;

FIG. 2 is a view similar to FIG. 1 of a second form of switching device in accord with the principles of the invention;

FIG. 3 is a top view of the switching device of FIG. 2 and;

FIG. 4 is a fragment of FIG. 2 with the mounting bracket of a pivotal operator incorporated in the device partly broken away to show the internal construction of the operator.

Referring now to the drawing, FIG. 1 depicts a nonsnap-acting switch in accord with the present invention. Switch 20 includes fixed contacts 22 and 24 and movable contacts 26 and 28, which are supported between the fixed contacts by a flexible, resilient contact support arm 30 configured to bias movable contact 26 into engagement with fixed contact 22. These components are housed in a casing or housing 32, which in-' cludes a base 34 and a cover 36. This housing completely surrounds the contacts and operating components of the switch and thereby keeps foreign matter from penetrating to the latter and causing malfunctions.

Contact arm 30 can be displaced or flexed to transfer movable contact 22 out of engagement with fixed contact 26 and movable contact 28 into engagement with fixed contact 24 by depressing an actuator 38. Terms such as depress and other terms relating to orientation are employed herein only for the sake of convenience and are not intended to be limiting or restrictive.) mounted in the base 34 of housing 32. Upon release of the actuator, resilient contact arm 30 restores to its original configuration, transferring the movable contacts back to the positions shown in FIG.

As discussed above, one of the advantages of our novel switching devices is that they can be readily made in extremely small sizes. For example, switches of the configuration shown in FIG. 1 have been made in which housing 32 was only about 0.6 inch long, 0.5 inch high, and 0.2 inch thick.

Referring again to the drawing, the base 34 of housing 32 provides end walls 39 and 40, top and bottom walls 42 and 44, and a side wall 46. A second side wall is provided by the cover 36 of housing 32, which is cemented or otherwise secured in a recess 48 in the base. This recess extends around the periphery of base 34 and provides a ledge 50 from which cover 36 is supported.

Apertures 52 are formed through base 34 at diagonally opposed corners of the housing. Suitable fasteners (not shown) can be inserted through apertures 52 to secure the switching device to a support.

As shown in FIG. 1, integral, upper and lower contact arm supports or backing portions 54 and 56 extend into the interior of housing 32 from the left-hand end wall 39 of base 34. Located between them is an integral, centrally projecting nose consisting of upper and lower bosses 58 and 60.

Between upper backing portion 54 and boss 58 and extending therefrom to the exterior of housing 32 is a channel 62 in which a rigid or non-flexible contact supporting arm 64 is cemented or otherwise secured. A second rigid or non-flexible contact supporting arm 66 is secured in a similar channel 68 between lower backing portion 56 and lower boss 60. A third rigid or non-flexible contact supporting arm 70 is secured in a channel 72 between the two bosses 58 and 60. Terminal apertures 74, 76, and 78, to which electrical leads (not shown) can be attached, are formed in the ends of rigid contact support arms 64, 70, and 66 exteriorly of housing 32.

The fixed contact 22 referred to above is attached to the lower side of the end of rigid contact support arm 64 inside housing 32. The second fixed contact 24 is supported in spaced, facing relationship to contact 22 by a flexible, resilient contact support arm 80. One end of support arm is fixed in any convenient fashion to the inner end of rigid contact support arm 66. Contact 24 is fixed to the opposite end of arm 80 and is accordingly supported in cantilever fashion from support arm 66 and housing 32 by the resilient support arm.

The two movable contacts 26 and 28 have generally trapezoidal cross-sections and are fixed to opposite sides of the lower leg 82 of resilient contact arm 30. This component is a unitary member which has a generally S-shaped configuration provided by leg 82, intermediate and upper legs 84 and 86, an arcuate portion 88 connecting legs 86 and 84 adjacent the lefthand end wall 39 of housing 32, and a second arcuate portion 90 connecting legs 84 and 82 adjacent the right-hand housing end wall 40.

The free left-hand end of lower resilient support arm leg 82 is connected in any convenient fashion to the inner end of the centrally located or middle rigidsupport arm 70. The opposite end of the S-shaped member; i.e., the free right-hand end of upper leg 86, terminates adjacent the right-hand end 40 of base 34 where it is engaged by the head portion 92 of actuator 38.

As is apparent from the drawing, actuator 38 is of the plunger type. This component is made from a plastic or other non-conductor. In addition to head 92, it. has a shank portion 94 which extends through an aperture 96 in the top wall 42 of housing base 34 and is therefore accessible from the exterior of housing 32'. Head 92 is made larger in diameter than the aperture 96 through the housing to retain actuator 38 in place.

As discussed above and shown in FIG. 1, the configuration of S-shaped member 30 is such that this member normally biases movable contact 26 into engagement with fixed contact 22 to complete a circuit'from terminal 74 through contact support arm 64, contacts 26 and 22, the S-shaped member 30, andcontact support arm 70 to terminal 76. As mentioned above, actuator 38 can be depressed to transfer contact 26 out of engagement with contact 22 and interrupt this circuit. At the same time movable contact 28 moves into engagement with fixed contact 24, completing a similar circuit between terminals 76 and'78.

' Initial depression of actuator 38 rotates the upper leg 86 of member-30 in a clockwise direction relative to middle leg 84. During this initial part of the actuator stroke, movable contact 26 remains in engagement with fixed contact 22. This provides the actuator pretravel referred to above and the consequent insensitiveness of the switch to small movements of the actuator. Accordingly, the designer and manufacturer can use much greater tolerances in the equipment in which the switch is incorporated than would be the case if slight movements of the actuator sufficed to transfer contact 26 out of engagement with fixed contact 22.

i As the downward movement of actuator 38 continues, member 30 flexes downwardly with lower leg 82 rotating in a clockwise direction. Accordingly, movable contact 26 moves away from fixed contact 22;. and movable contact 28 moves toward and engages fixed contact 24.

- Switch is designed so that the contact between contacts 24 and 28 occurs before actuator 38 reaches the end of its stroke. This is to provide reasonable tolerances in the manufacture of the switching device; i.e., it would be impractical to manufacture such devices on a volume basis so that the downward stroke of actuator 38 would terminate precisely in all cases as contact was made between contacts 28 and 24.

The provision of this overtravel does, however, require the use of a novel mounting arrangement for fixed contact 24. Specifically, if contact 24 were mounted in the same manner as contact 22; i.e., on a non-flexible arm, downward movement of the actuator after engagement of contacts 28 and 24 would bend leg 82 of member relative to le'g 84 and/or leg 84 relative to leg 86. This would result in a rapid increase in the resistance to downward'movement of actuator 38 and a consequent increase in the force required to depress the latter. This is undesirable, especially in smaller size switches where only a very few ounces of force may be available to operate actuator 38.

In the present invention, however, the resilient, flexible contact support arm flexes and allows downward movement of fixed contact 24 after the latter is engaged by movable contact 28 so that actuator 38 will be nearer the end of its stroke before the compression or bending of member 30 occurs. This significantly smooths out the increase in force necessary to move actuator 38 through the terminal portion of its downward stroke.

Movable contact 28 remains in engagement with fixed contact 24 as long as a downwardly acting force of sufficient magnitude remains on actuator 38. To return the switch contacts to the positions shown in FIG. 1, this force is removed from the actuator. The resilient, S-shaped member 30 then restores to its original, illustrated configuration, transferring the movable contacts back to their illustrated positions.

FIGS. 2-4 illustrate a non-snap-action switch 98 in accord with the principles of the present invention which is in many respects similar to the switching device 20 just described. To the extent that the components of the two switching devices are the same, they have been identified by like reference characters.

Switch 98 differs from switch 20 in that the rigid contact support arm 64 of the latter is replaced with a rigid or non-flexible contact support arm 100 having the same configuration as contact support arm 66. Fixed contact 22 is supported in cantilever fashion from this contact support arm by a flexible, resilient contact support arm 102 substantially identical to the flexible contact support arm 80 described above. One end of contact support arm 102 is fixed to contact support arm 100. Contact 22 is supported from the other end of flexible arm 102 and is therefore resiliently supported in cantilever fashion in housing 32.

The mounting of fixed contact 22 in the manner just described has two advantages. First, if the force retaining actuator 38 in the depressed position is suddenly removed, resilient, S-shaped contact support arm 30 will restore rapidly to its illustrated configuration. With fixed contact 22 rigidly supported in housing 32, movable contact 26 may strike and bounce away from fixed contact 22 if this occurs. With contact 22 mounted as illustrated, however, contact bounce will not occur. Instead, contact 22 will simply yield or give when engaged by movable contact 26; and the latter will accordingly remain in engagement with fixed contact 22.

Also, with the fixed contacts 22 and 24 mounted in cantilever fashion on flexible contact support arms, there is relative movement between the contact surfaces of the two contact pairs 26, 22 and 28, 24 as the contacts engage and disengage. The direction of such movement is shown by the double-headed arrow 104 in FIG. 2'. This relative movement is a wiping action and makes the contact surfaces self-cleaning.

Referring again to the drawing, FIGS. 24 also show how a pivot type operator 106 can be added to switching devices of the type described above to effect the downward movement of actuator 38. The major components of this operator are a generally U-shaped bracket 108, a L-shaped actuator engaging member 110, and an elongated, operating lever 112.

The web 113 of bracket 108 is fixed to the upper wall 42 of casing base 34 as by a rivet 113A and cement. The actuator engaging member 110 is pivotally supported from base 108 on pivot pin 114, which is supported in the vertical legs 115 of bracket 108 and extends through downtumed flanges 116 at opposite sides of the horizontal leg 1 17 of member 1 and a centrally disposed upturned flange 118 in leg 117.

Lever 112 terminates in a loop 120 fixed to the lefthand end of the leg 117 of L-shaped member 110 as by a rivet 122 and extends to the right as shown in FIG. 3 through the generally vertically oriented leg 124 of member 110. This connects the lever to member 110 for movement therewith. Accordingly, the exertion of a downward or clockwise force on lever 112 as shown in FIGS. 2 and 4 causes a similarly directed movement of the right-hand end portion 126 of leg 117 of member 1 10. There is a concurrent downward movement of actuator 38 as the upper end of the latter is engaged by the right-hand end portion of the L-shaped member.

The mounting of fixed switch contact 24 on a resilient, flexible contact support arm in the manner described above provides an additional advantage in embodiments of the invention such as that illustrated in FIGS. 2-4. More specifically, this permits the stroke of actuator 38 to be lengthened, thus providing increased actuator overtravel. The latter allows lever 112 to move through a wider arc in its operating stroke, which is an advantage in many applications of the invention.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by Letters Patent is:

1. An electrical switching device comprising a housing having spaced apart end wall means; a pair of fixed contacts supported in spaced apart relationship from one of said end wall means between it and the other of said end wall means; a movable contact means; a resilient, generally S-shaped contact arm supporting the movable contact means between and biasing it into engagement with one of said fixed contacts, one end of said resilient contact arm being fixed relative to said one end wall means of said housing and the other end thereof freely terminating adjacent the other of said end wall means; and actuator means movable relative to and accessible from the exterior of said housing and having a porition engageable with said resilient contact arm adjacent said other end wall means of the housing for displacing said resilient contact arm and transferring said movable contact means out of engagement with said one fixed contact and into engagement with the other fixed contact, said resilient contact arm having thee generally straight legs, a first arcuate portion connecting the first and second of said legs adjacent said other end wall means of said housing, and a second arcuate portion connecting said second and the third of said legs adjacent said one end wall means of said housing, said first leg of said resilient contact means lying between said fixed contacts and the second and third legs thereof being between said one of said fixed contacts and the contact support arm engaging portion of said actuator means.

2. A switching device according to claim 1, wherein said movable contact means comprises first and second contacts, said contacts being fixed to opposite sides of said resilient contact arm.

3. A switching device according to claim 1, including a pair of generally rigid contact arms supported from and extending through said one end wall means of said housing, said anns having terminal means exteriorly of said housing to which electrical conductors can be attached and one of said fixed contacts being supported from one of said rigid contact arms, and a resilient contact arm fixed to the other of said generally rigid contact arms and supporting the other of the fixed contacts therefrom.

4. A switching device according to claim 3, together with a further resilient contact arm fixed to said one of said contact arms and supporting said one of said fixed contacts therefrom.

5. A switching device according to claim 1, together with a generally rigid contact arm supported from and extending through said one end wall means of said housing, said one end of said resilient contact arm being fixed to said generally rigid contact arm and said generally rigid contact arm having a tenninal means exteriorly of the housing to which an electrical conductor can be attached.

6. A switching device according to claim 1, wherein said housing has a wall means extending between said end wall means, there being an aperture through said last-mentioned wall means and said actuator means having a shank portion extending through said aperture, the resilient contact arm engaging portion of said actuator means being a head having a diameter exceeding that of said aperture and said head being disposed between the interiorly facing side of the wall means in which the aperture is formed and said other end of said resilient contact arm.

7. A switching device according to claim 6, together with a bracket fixed to the exterior of the wall means in which the aperture is formed and a further actuator pivotally supported from said just-mentioned wall means by said bracket, said further actuator having a first portion engageable with the shank portion of the first-mentioned actuator and a second portion engageable to pivot said further actuator relative to said bracket means and thereby cause said first portion thereof to effect a movement of the first-mentioned actuator relative to said wall means.

8. An electrical switching device comprising a housing having wall means at one end thereof; first, second and third flexible contact arms interiorly of said housing; a first fixed contact cantilever supported in said housing by one of said flexible contact arms; a movable contact means supported by the second of said flexible contact arms in said housing opposite the first fixed contact; an actuator means accessible from the exterior of said housing for so flexing said second contact arm as to move said movable contact means toward or away from said first fixed contact; a second fixed contact cantilever supported from said housing wall means in spaced relation to said first fixed contact and on the other side of the movable contact means therefrom by said third flexible contact arm whereby, when said actuator means is operated, the movable contact means is transferred out of engagement with said first fixed contact and into engagement with the second of the fixed contacts; and rigid contact arms supported from said wall means, said flexible contact arms each being supported at one end thereof from one of said rigid contact arms, said rigid contact arms having terminal means to which electrical leads can be connected exteriorly of the housing, and the resilient contact arm by which the movable contact means is supported having three generally straight legs, a first arcuate portion connecting the first and second of said legs adjacent the end of said housing opposite the end at which it is supported by the rigid contact arm, and a second arcuate portion connecting said second and the third of said legs adjacent said one end of said housing, the first leg of said resilient contact means lying between said fixed contacts, the second and third legs thereof being between said second of said fixed contacts and the housing, and said third leg being engageable by said actuator means.

9. A switching device according to claim 8, wherein therein is an aperture through the wall means and wherein said actuator means has a shank portion extending through said aperture and a head portion interiorly of the housing, said head portion having a diameter exceeding that of the aperture in said housing wall means and said head portion bring engageable with said third leg of said actuator.

UNITED. STATES PATIENT OFFICE CERTIFICATE OF c0 QHN Patent 3.683.144 Dated August 8, 1972 I I Inventor) John W. Bowen and Donald D. Perkins I It is certified that error appears in the above-identifi'edpetent v and that said Letters Patent are hereby corrected as shown below:

Column 7 line58, 'porition" should be --po'rtion-. Column 7, line 64) "thee" should be --three-- Column 10, line 14, 'fbring" should be --1b eing--.

Signed and sealed this 20th day of March 1973;,

(SEAL) Attest: v

"EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attes'ting Officer I v Commissioner of Patents FORM P0-10S0 (10-69) USCOMM-DC 60375-P69 u.s. GOVERNMENT PRINTING OFFICE: I969 0-366-334 

1. An electrical switching device comprising a housing having spaced apart end wall means; a pair of fixed contacts supported in spaced apart relationship from one of said end wall means between it and the other of said end wall means; a movable contact means; a resilient, generally S-shaped contact arm supporting the movable contact means between and biasing it into engagement with one of said fixed contacts, one end of said resilient contact arm being fixed relative to said one end wall means of said housing and the other end thereof freely terminating adjacent the other of said end wall means; and actuator means movable relative to and accessible from the exterior of said housing and having a porition engageable with said resilient contact arm adjacent said other end wall means of the housing for displacing said resilient contact arm and transferring said movable contact means out of engagement with said one fixed contact and into engagement with the other fixed coNtact, said resilient contact arm having thee generally straight legs, a first arcuate portion connecting the first and second of said legs adjacent said other end wall means of said housing, and a second arcuate portion connecting said second and the third of said legs adjacent said one end wall means of said housing, said first leg of said resilient contact means lying between said fixed contacts and the second and third legs thereof being between said one of said fixed contacts and the contact support arm engaging portion of said actuator means.
 2. A switching device according to claim 1, wherein said movable contact means comprises first and second contacts, said contacts being fixed to opposite sides of said resilient contact arm.
 3. A switching device according to claim 1, including a pair of generally rigid contact arms supported from and extending through said one end wall means of said housing, said arms having terminal means exteriorly of said housing to which electrical conductors can be attached and one of said fixed contacts being supported from one of said rigid contact arms, and a resilient contact arm fixed to the other of said generally rigid contact arms and supporting the other of the fixed contacts therefrom.
 4. A switching device according to claim 3, together with a further resilient contact arm fixed to said one of said contact arms and supporting said one of said fixed contacts therefrom.
 5. A switching device according to claim 1, together with a generally rigid contact arm supported from and extending through said one end wall means of said housing, said one end of said resilient contact arm being fixed to said generally rigid contact arm and said generally rigid contact arm having a terminal means exteriorly of the housing to which an electrical conductor can be attached.
 6. A switching device according to claim 1, wherein said housing has a wall means extending between said end wall means, there being an aperture through said last-mentioned wall means and said actuator means having a shank portion extending through said aperture, the resilient contact arm engaging portion of said actuator means being a head having a diameter exceeding that of said aperture and said head being disposed between the interiorly facing side of the wall means in which the aperture is formed and said other end of said resilient contact arm.
 7. A switching device according to claim 6, together with a bracket fixed to the exterior of the wall means in which the aperture is formed and a further actuator pivotally supported from said just-mentioned wall means by said bracket, said further actuator having a first portion engageable with the shank portion of the first-mentioned actuator and a second portion engageable to pivot said further actuator relative to said bracket means and thereby cause said first portion thereof to effect a movement of the first-mentioned actuator relative to said wall means.
 8. An electrical switching device comprising a housing having wall means at one end thereof; first, second and third flexible contact arms interiorly of said housing; a first fixed contact cantilever supported in said housing by one of said flexible contact arms; a movable contact means supported by the second of said flexible contact arms in said housing opposite the first fixed contact; an actuator means accessible from the exterior of said housing for so flexing said second contact arm as to move said movable contact means toward or away from said first fixed contact; a second fixed contact cantilever supported from said housing wall means in spaced relation to said first fixed contact and on the other side of the movable contact means therefrom by said third flexible contact arm whereby, when said actuator means is operated, the movable contact means is transferred out of engagement with said first fixed contact and into engagement with the second of the fixed contacts; and rigid contact arms supported from said wall means, said flexible contact arms each beinG supported at one end thereof from one of said rigid contact arms, said rigid contact arms having terminal means to which electrical leads can be connected exteriorly of the housing, and the resilient contact arm by which the movable contact means is supported having three generally straight legs, a first arcuate portion connecting the first and second of said legs adjacent the end of said housing opposite the end at which it is supported by the rigid contact arm, and a second arcuate portion connecting said second and the third of said legs adjacent said one end of said housing, the first leg of said resilient contact means lying between said fixed contacts, the second and third legs thereof being between said second of said fixed contacts and the housing, and said third leg being engageable by said actuator means.
 9. A switching device according to claim 8, wherein therein is an aperture through the wall means and wherein said actuator means has a shank portion extending through said aperture and a head portion interiorly of the housing, said head portion having a diameter exceeding that of the aperture in said housing wall means and said head portion bring engageable with said third leg of said actuator. 